Thermographic instrumentation at 30 GHz (lower millimeter wavelength region) and at 1.5 GHz (lower microwave wavelength region) is being developed and evaluated physically preparatory to obtaining patient images depicting subcutaneous thermal abnormalities with accuracy and sensitivity improved over those achievable with conventional thermographic units operating in the micron wavelength infrared region. Because of the increased penetration depth of long wavelength thermography, data reflect thermal patterns from underlying tissues rather than the skin surface, as is the case with conventional thermography. Primary application of the proposed imaging techniques is to detection of breast cancer, although other applications such as assessment of skeletal inflammation also are being evaluated. In these applications, normal individuals and patients with known or suspected pathology will be included in clinical trials.